In copper pyrometallury industry, one method is producing blister copper indirectly from sulfide copper concentrate, which generally comprises two steps: first the sulfide copper concentrate is subjected to desulfurization and iron removal and smelting to obtain high-grade copper matte; and then the resulting copper matte is further subjected to desulfurization and iron removal and converting to give blister copper. Another method is producing blister copper directly from copper concentrate, which is adopted in practical production by Olympic Dam smeltery in Australia, Glogow smeltery in Poland, and KCM smeltery in Zambia. These methods have a common feature that the slag resulted from production contains Cu2O and Fe3O4 in a relatively large amount. In general, the slag contains 10% to 20% by weight of copper, and 30% to 50% by weight of Fe3O4.
Due to high copper content in slag, in all the above processes slag is treated by means of cleaning with electric furnace to decrease copper content in slag. During the cleaning with electric furnace, reducing agent is typically added to treat slag by reduction, and electric furnace could maintain temperature to guarantee thermodynamic foundation for reduction. However, cleaning with electric furnace merely provides thermodynamic foundation for reduction but leads to low reaction efficiency, such that the time for reducing Cu2O and Fe3O4 in slag is excessively long, i.e. the cleaning time is long, energy consumption is high, and the treated slag has a copper content of 1% to 4% by weight, i.e. the slag still has a relatively large copper content and needs to be subjected to further treatments like beneficiation before application. In this way, it causes the problem of relative high investment and production cost, and it is unfavorable for production.